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Biology > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (50):
1

Homeostasis

Maintaining a constant internal environment

2

Main sense organs

Skin
Eyes
Nose
Tongue
Ears

3

Reflex

Involuntary response to a stimuli

4

The neurones

Sensory
Relay
Motor

5

What happens across the synapse?

The electrical impulse from the presynaptic neurone causes the chemical messenger to fuse with the membrane diffusing the information across the synapse to the postsynaptic neurone in order for the movement to continue.

6

Reaction time

Time taken for a signal to be sent to the brain then to the relevant parts of the body to produce a response.

7

Cerebral cortex

The outer layer of the brain. Responsible for more complex activities.

8

Medulla

Long tube. Responsible for unconscious activities.

9

Cerebellum

Lump behind the medulla. Responsible for balance and muscular activity.

10

Pituitary gland

In front of the medulla. The master gland responsible for all other hormones.

11

Possible ways of studying the brain

MRI scan
Observe a person with brain damage
Electrical stimulation

12

Optic nerve

Made up of cells which have a cell body, axons and dendrites. Sends messages received by light receptors, at the brain the messages become visual images, there is no retina here so there’s a blind spot but your brain fills the gap.

13

Cornea

Transparent layer at the front of the eye. Lets light into the eye and refracts it a it enters so it is focused on the retina.

14

Lens

Held in place by ligaments and muscles. Main part of eye, fine tunes the light rays once they pass through the cornea.

15

Suspensory ligament

Connect to the ciliary muscles to the lens and holds it in place. This stretches and slacks as the muscles contract and relax to adjust the thickness of the lens.

16

Iris

Control the size of the pupil. Made up of muscles. It is important as it prevents damage caused by too much light.

17

Ciliary muscles

Change the shape of lens to increase or decrease refraction

18

Sclera

White outer layer. Tough and strong protection.

19

Retina

Back of the eye with the light receptor cells. When the light hits then they are stimulated and send impulses along the sensory neurones of the optic nerves.

20

Accommodation

Process of changing the shape of the lens to focus on near or distant objects.

21

What happens when you look at something close up?

1.muscles contract
2.ligament loosen
3.lens is thicker
4.light is refracted stronger

22

What happens when you look at something far away?

1.muscles relax
2.ligament strengthens
3.lens is thinner
4.less light is refracted

23

What happens to the eye when bright light is around?

Pupil constricts to prevent damage to the light receptors.

24

Proper name for short sightedness

Myopia

25

Proper name for long sightedness

Hyperopia

26

What is myopia solved with

Convergent lens

27

What is hyperopia solved with

Divergent lens

28

Thermogultation

The process that allows your body to maintain its core internal temperature 37 degrees Celsius.

29

Vasodilation

Your blood vessels get bigger to get rid of heat

30

Vasoconstriction

Blood Vessels get smaller so that you lose less heat

31

Hormone

A chemical messenger
They are secreted from glands and travel in the blood

32

Endocrine system

Collection of glands that release hormones into blood

33

What does the pituitary gland do?

These hormones act on others glands to stimulate other hormones to be released to bring effects.

34

What does the pancreas do?

Responsible for controlling blood sugar levels. It produces and balances the concentration of insulin and glucagon.

35

Insulin

Lowers blood sugar levels.

36

Glucagon

Increases blood sugar levels

37

Menstrual cycle

Regular natural changes that occur in the uterus and ovaries that makes pregnancy possible.

38

FSH follicle stimulating hormone

Causes egg to mature.

39

LH luteinising hormone

Stimulated the release off the egg at ovulation

40

Oestrogen

Stimulates build up of lining

41

Progesterone

Maintains the lining of the uterus

42

Contraceptives

Oral contraceptive that inhibits FSH production
Surgical methods
Injection or patch to slow release progesterone
Cap to place over cervix
Barrier methods like condoms
Intrauterine devices (inserted into uterus) to prevent implantation of embryo or release progesterone
Spermicidal agents to disable sperm

43

In-vitro fertilisation

1.FSH and LH is injected into the mother to stimulate eggs maturing .
2. Remove an egg from the ovary
3. Fertilise egg and it forms an embryo
4. The embryos are inserted into the mothers uterus and the baby can develop

44

What are plant hormones called?

Auxins

45

What do auxins do?

Cause tropisms which are growth responses to certain things

46

Phototropism

A response to light

47

Hydrotropism

A response to water

48

Gravitropism

A response to gravity

49

How to auxins work?

When axons are disrupted evenly the plant goes straight up, when the sun fit example moved to the right the auxins move to the left causing more growth on the left causing the plant to tilt right towards the sun

50

Tissue culture

Cutting is first taken from the plant with desired characteristics, cut end is dipped in root powder. These hormones stimulate the growth of new roots helping it grow into a new plant.